1. Field of the Invention
This invention relates to a camera lens which is provided with a holding grip called a lens grip by the side of a barrel and which contains therein an extender optical system for extending the focal length and other optical system and in which the optical systems are provided insertably into and removably from the optic axis of a photo-taking optical system (hereinafter referred to as "the extender-containing camera lens with a grip").
2. Related Background Art
The lens shown in FIGS. 1A and 1B of the accompanying drawings is a prior-art extender-containing camera lens with a grip. This camera lens with a grip is indispensable to the recent portable television cameras, particularly, ENG (electronic news gathering) cameras.
In FIGS. 1A and 1B, reference numeral 1 designates a lens barrel, and reference numeral 2 denotes a lens grip comprising a body 2a fixed to the lens barrel 1 and a removable grip cover 2b of readily graspable shape. Reference numeral 3 designates a removably insertable portion of an extender optical system which is a part of the lens barrel, reference numeral 4 denotes the extender optical system, and reference numeral 6 designates a change-over lever for operating the extender optical system. The extender optical system 4 may be inserted into a position 5a in the optic axis of the photo-taking optical system by the change-over lever 6 being pivotally moved, and may be retracted to a position 5b outside the optic axis. Reference numeral 7 denotes a mount for mounting the lens onto a camera, reference numeral 8 designates a belt, reference numeral 9 denotes a pad to which the back of a hand may be applied to support, and SW1-SW4 designate various switches. SW1 is a zoom seesaw control switch, SW2 is an iris momentary switch, SW3 is an external picture switch, and SW4 is a VTR switch. Reference character 10a denotes a zoom ring, and reference character 11a designates an aperture ring. Various mechanisms are contained in the lens grip 2. Reference character 10b denotes a zoom position detecting element, reference character 11b designates a diaphragm position detecting element, reference character 10c denotes a zoom drive motor, and reference character 11c designates a diaphragm driving motor.
The extender-containing camera lens with a grip as described above is mounted on a television camera on band (such as an ENG camera or a household video camera). Each of most users (cameramen) places the camera body (not shown) on his right shoulder and levels the camera with the right-hand lens grip of the lens barrel as viewed from the camera side being grasped by his right hand. The user operates the zoom seesaw control switch SW1 and pushs button switches SW2 and SW3 by the index finger and middle finger of his right hand and operates the push button switch SW4 by the thumb of his right hand. Further, he pivotally operates the change-over lever 6 to effect insertion and retraction of the extender optical system 4 and change over the focal length of the photo-taking optical system.
By his left hand, be rotatively operates the operating member of the lens barrel 1, such as the focusing ring or the zooming ring.
Such a prior-art extender-containing camera lens with a grip is designed such that when the camera is not in use, the extender optical system 4 is retracted to the side opposite to the side on which the lens grip 2 is provided, i.e., the left side of the lens barrel 1 as viewed from the camera side. Accordingly, the bulged portion 3a of the removably insertably portion 3 of the extender optical system protrudes to the left side of the lens barrel 1.
When the cameraman places a television camera provided with such lens on his right shoulder as previously described and tries to operate the operating member of the lens barrel 1, such as the focusing ring or the zooming ring, by his left hand, a problem may arise in that the movement and position of the left hand is limited by the bulged portion 3a and that even if he tries to see the index mark or the scale indicated on the lens barrel 1 during photography, his view is obstructed by the bulged portion 3a to make it difficult to see the index mark or the scale.
Furthermore, the bulged portion 3a of the removably insertable portion 3 of the extender optical system forms a part of the lens barrel 1 and therefore, sufficient strength and rigidity are required of it, and if these requirements are met, the weight of the bulged portion 3a will become heavy. Also, in the prior-art lens with a grip, whether it is or is not provided with an extender, the grip 2 is attached to the lens barrel 1 by means of a screws as shown in FIG. 1B. If at this time, the camera is supported by the grip, the supporting force will be exerted on the lens barrel. Accordingly, in the prior-art lens with a grip, the strength and rigidity of the lens barrel 1 must be made high and thus, the weight of the entire lens barrel becomes heavy. Particularly, if such a prior-art lens is mounted on a portable camera, there will arise a problem that the balance with which the camera is leveled is aggravated to make the camera difficult to use.